Breaking the kinetics-load dilemma in zinc-ion capacitor thick electrodes via structure-interface synergy: Hierarchical nanoarchitectures with dual-site adsorption energetics modulation

The thick electrode of zinc ion capacitors (ZICs) is limited by the performance contradiction between fast reaction kinetics and high-quality load. The key to break through this bottleneck is to clarify the multi-physical field coupling mechanism inside the electrode and reveal the synergistic energy storage law of ion cross-scale transport and interface adsorption/desorption. In this study, a “structure-interface” collaborative optimization strategy was proposed: based on the natural wood framework, a three-dimensional interconnected multi-level pore network was constructed by resin to realize the precise matching of pore size and hydrated zinc ions, and N/O diatomic doping was introduced to regulate the surface charge distribution. The WPNK2 electrode exhibits a satisfactory capacity of 5.8 mAh cm^–2 and maintains 1.9 mAh cm^–2 at 200 mA cm^–2. At the same time, it provides a surprising capacity of 10.9 mAh cm^–2 when the load is increased to 82.75 mg cm^–2. Combined with in-situ spectroscopy, DFT, and electrochemical kinetic analysis, the multi-level energy storage mechanism of ion transport and interface adsorption in thick electrodes was revealed. This work provides a full-chain research paradigm of “structural design-interface engineering-mechanism analysis” for solving the “kinetics-load” trade-off problem of thick electrode materials, which will promote the development of high energy density ZICs devices.